Gravity

That Constant Longing

Were it not for the constant longing of gravity I would fly

It is an odd thing, gravity. Magnetism is what it is, keeping my iron feet glued to the loving surface of the Earth.

I was told as a kid that if the Earth stopped spinning, we’d all fall off; sort of rise up into the air, the Earth letting go of us (is how I pictured it) as we sailed for the moon. I didn’t quite see it then (but I took Mom’s or Dad’s or Whoever’s word for it) and I don’t see it now — wouldn’t it work in just the opposite way? With no gravity to counter the centrifugal force of spinning at a thousand miles an hour (at the equator), would we not hug the Earth a little closer, or at least feel a little heavier.

These days I don’t have to take anybody’s word for anything. I can just nod and then go home and Google it. Then, from the endless list of facts and various alternate facts and opinions, I choose who I trust.

Consider it done.

Thus spake Google (contradicting my childhood info) in summarizing the good news: If the Earth’s rotation stopped, we would not fall off.

So there, Mom or Dad or Whoever. Not that it will stop anytime soon.

Still, Google does go on to say, the Earth’s rotation is slowing. No, not drastically by any stretch. Estimates vary, but the consensus seems to be that our days grow by about two milliseconds every century or so, which (and I did the math) would mean that at the current rate we may come to a standstill in about 1.5 trillion years from now.

Not on top of my worry list.

But, just for the hell of it, let’s posit that God or Aliens or Something suddenly and completely froze the planet in its rotating tracks, no more spinning around its axis. What then?

Well, first of all, everything on the planet’s surface would not stop at the same rate but would continue its thousand miles an hour journey east, a shit storm to end all shit storms in other words, and that would probably take care of most of the population, whether human or animal — imagine the oceans, racing east at a thousand miles an hour over still-standing beaches and coastal cities. Not a pretty sight.

But let’s assume that we all survive this sudden full stop, and the planet now sits there, absolutely still — though still traveling around the sun at about a thousand miles a minute.

Picture then that half of the planet would now almost continuously face the heat of the Sun, while the other half would face the cold of space. Boiling hot versus freezing cold, in other words. That would see a wild migration of both man and beast toward the two narrow twilight zones between the hot and cold halves. But, of course, this twilight zone would slowly creep around the planet over the year, as the Earth does its annual Sun orbit.

Meanwhile, the oceans facing the sun would evaporate and the oceans facing the, well, not-sun, i.e., the other stars, would freeze.

But let’s pretend they don’t. Say they stay liquid and let’s only look at what I worried about as a kid, the centrifugal force.

Here’s the amazing thing: Over billions of years, the centrifugal force, which effectively pushes outwards, has made the planet a bit fatter around the middle (where it spins the fastest) with the tangible result that the Earth diameter measured through the equator is now about 21.4 kilometers longer than the Earth diameter measured pole to pole. Of course, this bulge in the solid Earth has taken billions of years to slowly develop since solid matter moves at a snail’s pace (slower than that) in response to the outward force caused by the spin of the planet.

The liquid water (our oceans) on the other hand, is far more responsive to this force with the result that the Earth’s spin has pushed this liquid water to an anomalous elevation of about eight kilometers. Meaning in turn that thanks to the spinning Earth, at the equator the water has now been raised some eight kilometers higher than where it would have been had there been no spin to the Earth. And consider along with this the fact that around the equator the deepest part of the oceans is only about 5.75 kilometers.

Meaning: Take away the spin and you take away all water at the equator. In fact, should the Earth stop spinning, little by little the oceans would migrate towards the poles from the equator. At first, the retreating waters would reveal only small regions of terra firma around the equator but eventually, there would be a huge mega-continent wrapped around the Earth’s midsection. In other words, you could walk around the Earth along the equator and stay on dry land — ignoring the freezing cold on the night side, and the searing heat on the dayside, of course.

Now, the water that migrated from the equatorial band would have to go somewhere, and that somewhere would be the poles resulting in two separated polar oceans on each side of the equatorial mega-continent.

In the north, Canada would now be entirely underwater. And (following the line of the border of the current-day USA and Canada) all of Greenland, as well as the northern plains of Siberia, Asia, and Europe would be ocean floor. But Spain would mostly stay above water — buy real estate in Madrid would be my suggestion.

On the other side of the equator, the new Southern Ocean would start roughly on a line running through current-day Canberra, Australia. Africa would be joined to Madagascar, while Australia would be joined to New Guinea and Indonesia.

Now it’s not just the spin of the Earth that has given us today’s eight-kilometer-high bulge of water at the equator. The other factor is gravity (which is how this musing began, remember).

The poles are about 10 kilometers closer to the center of the Earth than the equator, so the gravity is a tiny bit stronger at the poles, which is would pull the water away from the equator toward the poles.

All of the above: Earth circa today plus 1.5 trillion years.

As for today and gravity: I sometimes think that gravity is affinity on the physical plane, the yearning to embrace, cling to one’s chest as it were, which is what our little home planet is engaged in ongoingly. No?

© Wolfstuff

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